We're still getting many questions asking if the Rx amp can drive a particular set of Cans/IEMs/etc, so I posted this video on YouTube of an Rx driving two 4 Ohm 12" subwoofers.
I'd say it's pretty safe to assume that if the Rx can pound Metallica's Black album on two 12" subwoofers for over 18 hours without needing a recharge, it can pretty much handle any 'phone we throw at it (especially low impedance and multi-way designs).
Matt MacBeth
GR9 Technologies